Wednesday, January 30, 2019

Crustacean Life Cycles

CRABS: The crab life cycle consists of a stage called a Zoea, which is usually planktonic. Zoea look nothing like adult crabs. They are transparent, have elongate, shrimp like abdomens, and have long spines protruding from their backs. Over time, they change into the Megalops, which has more of the adult crab features, including claws, though the abdomen still trails out behind them. As they mature, the abdomen retracts under the body, officially entering the juvenile stage. After that point, they mostly grow bigger, with minimal physical changes, until they reach reproductive maturity.

SHRIMP

The shrimp's life cycle undergoes many stages. It starts with a small, feathery, planktonic larva called a Nauplius. Over time, the Nauplius elongates, and turns into a Zoea, at which point its appendages begin to specialze, and mouth parts develop. It then undergoes a the Mysis stage, when the swimmerets and walking legs are distinguished fom each other. It then grows, through the juvenile stage, before finally becoming an adult.

LOBSTER:

The Lobster life cycle is much more linear, with a series of stages that progress over the course of several weeks. Then there are no physical changes for months, only size increase until reproductive maturity.

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